<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            /* padding: 0; */
        }
        #div1{
            background-color: green;
        }
        /* ul 自带padding-left：40px */
        ul{
            list-style-position: inside;
            /* 默认值在外面 */
            /* list-style-position: outside; */
            list-style-type: decimal; 
        }
        li{
            background-color: red;
        }
    </style>
</head>
<body>
    <div id="div1">
        <ul>
            <li>北京</li>
            <li>上海</li>
            <li>广州</li>
        </ul>
    </div>
    
</body>
</html>